The present invention relates to a process for converting glycol di-tertiary alkyl ether (referred to hereinafter as DAE), and particularly to a process for converting DAE into at least one of glycol mono-tertiary alkyl ether (referred to hereinafter as MAE) and tertiary alcohol, or tertiary olefin.
DAE is produced as a by-product when glycol mono-tertiary alkyl ether is produced by reacting glycol with tertiary olefin in the presence of an acid catalyst, as described, for example, in U.S. Pat. No. 3,317,483. Although MAE is useful as a solvent, a dispersing agent or a diluent, etc., in the industrial fields of coatings, inks, etc., DAE is of relatively little value. Accordingly, it would be very desirable if the DAE could be converted into more useful compounds such as glycol monoethers or alcohols. However, a process for converting DAE has not been known heretofore.
It has been known to obtain alcohols by reacting ethers such as dialkyl ether with water in a presence of sulfuric acid, hydrochloric acid, low molecular weight organic sulfonic acid (for example, benzenesulfonic acid, paratoluenesulfonic acid, sulfoacetic acid or sulfolauric acid), and fluoroacetic acid or chloroacetic acid, but when such a known process is applied to DAE, considerable amounts of oligomers of tertiary olefin, such as dimers or trimers of tertiary olefin, etc., are formed in addition to MAE, tertiary alcohol, and tertiary olefin (e.g., see Comparative Examples 1 and 2 hereinafter). In the case of industrially obtaining MAE and tertiary alcohol from the above described production mixture by means such as distillation, the presence of oligomers of tertiary olefin not only causes lowering of the yield of the desired product, but also requires a complicated separation means. Further, there is a problem in that the oligomers are present into the tertiary alcohol and/or MAE as impurities.
As processes for producing tertiary alcohol, a process which comprises sulfurizing tertiary olefin and hydrolyzing the product, and a process which comprises directly hydrating tertiary olefin have been known. However, they have a problem in that, since a mixed olefin fraction is necessarily used as the tertiary olefin feed, a part of the other olefins included in the mixed olefin fraction reacts to produce secondary alcohol as a by-product, as a result of which the desired tertiary alcohol is difficult to obtain in high purity.